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Speeding the Field Drying of Alfalfa with Chemicals
No full textField drying experiments were conducted on alfalfa to determine the requirements and long term expected performance of chemicals for conditioning hay in the northern USA 2.8% aqueous solution of potassium carbonate (K2CO3) sprayed on the alfalfa as it was mowed increased field drying rate. A mixture of 1.4% potassium carbonate and 1.4% sodium carbonate (Na2CO3) in water provided a similar increase in drying rate, while a solution of sodium carbonate alone was generally less effective. Maximum effect occurred when the treatment was applied as alfalfa was mowed and conditioned with a roll-type conditioning machine and the alfalfa was left to dry in a thin swath. Application rate affected drying performance. Rates of 450 liter/ha on heavy crop yields (\u3e3.0 t dry matter/ha) and 300 liter/ha on lighter yields were required to obtain adequate coverage of the plant material. Increasing concentration of potassium carbonate above 2.8% did not improve drying. Neither nozzle type nor operating pressure of the spray system influenced drying performance at proper application rates. The chemical treatment was generally less effective on first cutting alfalfa because heavier swaths and wet soil inhibit drying. On later cuttings, drying rates were normally increased 34 to 45% which reduced field curing time by 1/2 to 1 day in the northern US
Possibility of Control of Urophlyctis Alfalfae, The Crown-wart Agent of Alfalfa, by the use of Cultivars Tolerant to Soil Wetness
No full textUrophlyctis alfalfae, the crown-wart agent of alfalfa, is locally damageable in France in damp or irrigated fields. Field tests, from 1980 to 1983, in plots naturally contaminated by Urophlyctis alfalfae show that among 9 alfalfa cultivars, only those known to be tolerant to soil wetness have a good resistance to U. alfalfae ( Paider and 2 old french cultivars Marais de Challans , Marais de Lm;on ). The use of such cultivars in damp soils would allow to reduce the damages of this disease. The resistance of the 2 old cultivars may have been naturally selected in marshlands where the disease is endemic. The tolerance of alfalfa to what is commonly called soil wetness may be partly due to a better resistance to U. alfalfae
The Cultivation and Feeding Value of Persian Clover
No full textResearch with Persian clover (Trifolium resupinatum, ssp. majus) cv. Mara!, in south eastern Australia shows it to be productive and well adapted to waterlogged soils. It is particularly productive in spring when compared with other clovers. Winter production can be increased by sowing Persian clover with Westerwolds ryegrass or oats but the yield of clover in the spring is therby reduced. Persian clover conserved as hay was found to have a low neutral detergent fibre content (28.1 % ). In a 60 day feeding trial, lambs were fed Persian clover hay (78.5% digestible dry matter), lucerne hay (63.0% DDM), grass/sub. clover pasture hay (62.0% DDM) or oaten hay (59.9% DDM). The dry matter intake (DMI) for Persian clover hay and lucerne hay was 1.3 and 1.2 kg/day respectively. Fasted liveweight gain (LWG) was considerably greater for the former hay (viz. 0.16 kg/day vs. 0.09 kg/day). Grass/sub. clover and oaten: hays were low in feeding value with DMI less than 1.0 kg/day and LWG less than 0.06 kg/day. Persian clover hay containing c 20% Phalaris aquatica also resulted in increased LWG of cattle relative to those fed lucerne hay (0.69 vs. 0.50 kg/day)
Interploidy Transfer of Germplasm in Red Clover 2N Gametes
No full textA program was designed to sexually produce tetraploid red clover, Trifolium pratense L. adapted to the northern zone of the United States using 2n gametes to effectively transfer diploid (2x) germ plasm to the tetraploid ( 4x) level. Both unilateral (2x-4x and 4x-2x) and bilateral (2x-2x) crosses were conducted using diploid parents which produced 2n gametes. Red clover genotypes were isolated which produced an average of 0.21 2n eggs per 1000 and 12 and 16% tetraploids in unilateral and bilateral crosses, respectively. Genotypes were also identified which either produced 2n pollen exclusively or at a high frequency. Tetraploid and fertile triploid (3x) progeny were derived from bilateral crosses. It was concluded that by using 2n gametes diploid germplasm can be effectively transferred sexually to the tetraploid level, thus avoiding the inbreeding effects which occur with the conventional procedure of chromosome doubling using chemical agents. In addition, 2n gametes may be useful in interspecific germplasm transfer in Trifolium
Effect of Long-Term Subfreezing Seed Storage on Forage Production of Eight Grass Cultivars
No full textGrass seeds stored 20 years at subfreezing temperatures germinated well under sterile laboratory conditions in earlier studies. This study was conducted to determine whether forage yields from seeds stored 22 to 26 years at subfreezing temperatures were comparable to those from fresh seeds. Included were seed of eight cultivars: three cultivars of orchardgrass (Dactylis glomerata L.), two of smooth bromegrass (Bromus inermis Leyss.), two of timothy (Phleum pratense L.), and one of meadow fescue (Festuca elatior L.). Fresh_ and stored seed of each cultivar was planted in field plots in April 1984. Each entry was replicated five times m plots measunng 4 m each. Results are based on two forage harvests in year of establishment. Season total yields ranged from 8.0 to 12.5 metric tons/hectare dry forage. Within cultivars forage yields from 22 to 26-year-old stored seed did not differ from those of fresh seed with the exception of one orchardgrass cultivar. Stored seed that tested viable in laboratory tests generally produced as well in the field as fresh seed, but stored seed of S-143 orchardgrass lacked vigor and performed poorly in the field
FACTORS IMPACTING GERMINATION, EMERGENCE, AND ESTABLISHMENT OF DIRECT SEEDED AND TRANSPLANTED HEMP (CANNABIS SATIVA L.)
No full textIndustrial hemp (IH) establishment has many challenges including: poor emergence, low stand establishment, and variable plant development in direct seeded hemp. In floral hemp production, quality transplant production is a challenge with seedlings often becoming root bound and etiolated. In both direct seeded and transplant hemp, the relationship between root vigor and vegetative growth has not been studied and may prove insightful for managing emergence and establishment challenges. The goals of this study were three-fold: 1) to measure and describe root system architecture (RSA) and root phenotypes observed in selected IH cultivars especially in regard to identifying agronomically important RSA traits; 2) To explore emergence, stand establishment, plant growth, and correlating RSA features to better stand establishment in IH cultivars grown for both dual purpose (DP) and fiber (F) production; and 3) to explore how plant growth regulators (PGRs) may help manage early root and shoot growth in transplanted floral hemp (TFH) and the impacts these chemicals may have on mature plants and floral yield. Both two and three dimensional (2D & 3D) root phenotyping was conducted on a selected population of three hemp morphotypes (Chinese [CH], Grain/Dual [GD], and Fiber/Feral [FF]). Differences in 2D imaging revealed greater median number of roots and root tips in the CH morphotypes compared to the GD. The 3D data revealed differences among morphotypes at discrete timepoints from differences in rooting depth, width, and rooting lengths of both total and thicker roots (0.5 – 1.0 mm). Early stand establishment observations demonstrated: that a high proportion of live seed planted apparently never emerged, uneven emergence and seedling development contributed to further plant losses between establishment and harvest as late emerging smaller plants struggled for resources, and when coupled with RSA data collected on the same group of cultivars some poor stand establishment may be attributed to a lack of robust root growth and development. For transplanted hemp, a gibberellic acid (GA) blocker plant growth regulator, prohexadione calcium (PCa) was used as a substrate drench at rates ranging from 0 to 300 mg L-1 to manage growth of hemp transplants. This PGR, is involved in reducing cell elongation after initial cellular division, and thus acts as a plant growth retardant to try and manage stem etiolation and root binding. Rates of PCa ranging from 75 – 150 mg · L-1 were found to slow root and shoot growth in transplant production. These rates did not negatively impact final floral yields, though higher concentrations (300 mg · L-1), greater abiotic stress conditions, and cultivar selection may impact these results. To overcome early stand establishment challenges in IH, seed emergence, even seedling development, and selecting for cultivars with vigorous rooting depths, greater total lengths, and wider rooting perimeters are needed in direct seeded hemp. In transplanted hemp poor transplant quality due to etiolation and root binding can be managed through utilizing PCa (75 – 150 mg · L-1) without negatively impacting final floral yields. When taken in its entirety, this work provides valuable information for improving hemp management, and also suggests specific areas of research to improve emergence and establishment in direct and transplanted hemp
FAMILY AND SOCIAL FACTORS IN EMOTION REGULATION AND ADJUSTMENT IN ADOLESCENTS
No full textAdolescents face many challenges during this unique phase of development. Because of this, it is important to identify how to promote resilience and positive adjustment for these individuals. The present dissertation includes three studies which focused on familial and social factors in promoting emotion regulation and ultimately adjustment among middle and late adolescents.
The first study focused on the importance of alexithymia in the relationships between closeness and communication and internalizing problems, namely depression, anxiety, and self-esteem. Results showed that closeness was negatively associated with depression and positively associated with self-esteem. Communication was not associated with any of the studied internalizing problems. Alexithymia moderated the relationship between closeness and anxiety, but none of the other tested relationships were moderated by alexithymia.
The second study focused on the longitudinal relationships between emotional security in the family and both psychological well-being and distress; it also tested the potential mediating role of mental toughness. Results found a negative longitudinal relationship between Time 1 emotional security and Time 4 distress; it also found a positive longitudinal relationship between Time 1 emotional security and Time 4 well-being. Time 2 mental toughness was a significant mediator in model for well-being, but not in the one for distress.
The third study examined the correlates of resilience in late adolescent college students and tested the potential moderating role of sex. The correlates studied were sensory processing sensitivity, attachment security, maternal closeness and communication, as well as interpersonal support. Results indicated that sensory processing sensitivity, attachment closeness, and interpersonal support were unique correlates of resilience, maternal closeness and communication were not in the overall sample (i.e., both males and females). Although closeness was unrelated to resilience, multigroup moderation tests by sex provided evidence that closeness was positively associated with resilience, for males but not females. No other sex differences were found
SEX-SPECIFIC ROLES OF THE ADIPOCYTE MINERALOCORTICOID RECEPTOR IN OBESITY AND EARLY LIFE STRESS
No full textObesity is a burgeoning health epidemic caused by chronic overnutrition and exacerbated by genetic, environmental and developmental factors. The adipocyte mineralocorticoid receptor (MR), a transcriptionally active nuclear receptor, is speculated to contribute to metabolic dysfunction in the obese state. MR expression is increased in obese adipose tissue, and MR modulates the expression of fat-derived hormones such as leptin and adiponectin. In women, obesity can be exacerbated by early life stress, such as adverse childhood experiences (ACEs). Studies show that women display a positive association between cumulative ACE exposures and increased body mass index. Previously, we demonstrated that maternal separation and early weaning (MSEW) is a mouse model that recapitulates sex-specific effects of early life stress, and that chronic MR antagonism reduces exacerbated adiposity in female mice.
Therefore, we hypothesized that adipocyte MR deletion reduces fat expansion and improves glucose homeostasis, particularly in obese female MSEW mice. To test this hypothesis, we developed an inducible adipocyte-specific MR knockout mouse model. Control and MSEW mice were generated and randomized by genotype, wherein tamoxifen treatment resulted in mice with intact MR (AdipoMRfl) or deleted MR (AdipoMRKO). Five-week-old male and female mice were placed on an obesogenic high-fat diet (HFD), then body weight and composition were followed into adulthood. At 14 weeks of age, deletion of the adipocyte MR was induced, and body composition, glucose tolerance and metabolic profile were assessed after 4 weeks.
In control male mice fed HFD, deletion of the adipocyte MR improved glucose tolerance, reduced insulin resistance, and upregulated glucose handling genes in adipose tissue. Additionally, AdipoMRKO male mice showed increases in the metabolically-sensitizing hepatokine FGF-21, and upregulation of FGF-21 co-receptor β-klotho. MSEW blunted these insulin sensitizing effects. As expected in female mice, MSEW increased obesogenic response to HFD compared with controls prior to MR deletion. However, tamoxifen treatment reduced fat mass and improved glucose homeostasis only in MSEW AdipoMRfl mice, suggesting a beneficial role of an MR-dependent estrogen receptor modulation. Altogether, these studies provide insight into the multi-factorial roles of the adipocyte MR under obese conditions, which can be modified in a sex-specific manner by early life stress exposure
Internalism, Externalism, and the Phenomenology of Epistemic Justification
No full textThis dissertation applies a phenomenological method of analysis to the dispute between analytic internalists and externalists regarding epistemic justification. Traditionally, the justification condition on knowledge has been interpreted as an internal condition, but the growing popularity of the externalist antithesis has placed internalism on the defensive. Ultimately, however, the dispute appears to have fallen into an impasse. I identify a set of four arguments or cases that, when taken together, prompt us to adopt a set of contradictory conclusions about the necessary and sufficient conditions for justified belief. Moreover, none of the analytic views of justification surveyed seem to be capable of accounting for all four cases together. The entrenchment of this impasse suggests the need and the opportunity for an alternative method of analyzing the problem. I propose that Husserlian phenomenology can provide us with the tools needed to not only carve a way through the impasse but also salvage internalist theories of justification. Following this, I outline a phenomenological theory of justification that I call phenomenological evidentialism, the basic thesis of which is that certain experiences confer justification on a belief by virtue of a subject’s having conscious access to evidence through an act of originary, evidential intuition. I then show how phenomenological evidentialism can provide a plausible and consistent account of each of the four arguments or cases that constitute the impasse. I conclude by arguing that my view is in the best position to capture the internalist intuition that justification is tied to rationality
SPATIALIZING THE TAX CODE: USING PROPERTY RECORDS TO LOCATE THE FISCAL FACE OF RENTIERSHIP
No full textThis dissertation analyzes how the tax code shapes housing financialization in mid-sized US cities. Employing a mixed-methods approach that integrates critical computational analysis with qualitative fieldwork in Memphis, I examine the role of public rent-seeking in shaping housing financialization in U.S. cities. The first article analyzes the property tax appeal strategies of corporate landlords and their implications for public revenues and municipal budgets. The second article explores how the IRS 1031 exchange provision—which allows for capital gains deferrals when the proceeds of a property sale are reinvested in a ‘like-kind’ property—facilitates the movement of capital from high-cost coastal markets into ‘turn-key’ rental investments in Memphis, Tennessee, driving a retail driven form of housing financialization in the city. The third article tracks the connective tissue that enables this fiscally driven economy in local property management companies. I show how property management networks play a vital role in consolidating and making a market for geographically dispersed pools of retail capital, largely from high-cost coastal markets like California and New York. Collectively, this three-article dissertation contributes to urban, digital, and financial geography by showing how fiscal geographies shape the political economy of contemporary U.S. cities and by calling for greater geographic engagement with the spatial politics of taxation